This invention relates to a method of allowing air to escape from a tube for containing a fluent material such as caulking.
In the prior art, fluent materials, such as caulking, adhesives, or other materials, are typically stored in tubes that are generally cylindrical and extend from a rear end to a front nozzle. A plunger is received within the rear end and advanced by a gun to dispense the material from the nozzle. Historically, these tubes have been formed of cardboard. More recently, plastic has started to be used to form the tubes.
Problems exist in storing some types of materials in plastic tubes. As an example, when storing silicone-based caulkings, it is necessary to displace air outwardly of the tube once the plunger is inserted into the tube. The air could cause the silicone caulking to begin to set, which would be undesirable. The prior art has utilized an air tap that includes a needle on the filling machine that moves downwardly into the material to allow the air to escape while inserting the plunger.
This solution is unduly complicated. Moreover, it has not been applied to other types of caulkings. As an example, acrylic latex caulkings need not have the air removed. Thus, the art has not utilized such a complex method step to assist in removing air. Even so, it would be desirable to develop a simple air escape system that could be utilized on all of the different types of materials stored in these tubes.
These tubes also experience complications with undesired after flow of material from the nozzle. In particular, when a dispenser initially stops dispensing, there is sometimes additional forward flow of the material due to air within the tube. This causes some of the material to escape outwardly of the nozzle.
The present invention discloses a way to allow the air to escape between the plunger and the tube, while still maintaining the fluid-tight connection necessary to prevent undue leakage of the caulking or other material rearwardly between the plunger and the tube.